scholarly journals Fabrication of PVA/ GO Nanofiber Films by Electrospinning: Application for the Adsorption of Cu2+ and Organic Dyes

Author(s):  
Yao He ◽  
huafeng tian ◽  
Aimin Xiang ◽  
Songbai Ma ◽  
Duoyuan Yin ◽  
...  

Abstract In recent years, the treatment of water pollution has been a challenging and far-reaching topic. In order to improve the adsorption performance of polyvinyl alcohol nanofibers, a new nano-adsorbent graphene oxide was introduced into them in this work. The introduction of GO greatly increases the adsorption of Cu2+, Methylene blue (MB) and Congo Red (CR). The adsorption kinetics and isotherm analysis of the PVA/GO nanofiber film during the adsorption process showed that the adsorption of Cu2+ and MB by PVA/GO nanofiber film was mainly chemical adsorption, while the adsorption of CR was mainly physical adsorption. The adsorption process of PVA/GO nanofiber film on Cu2+ was in line with the Langmuir isothermal adsorption model, that is, single molecular layer adsorption, the distribution of adsorption active sites was relatively uniform, and the increasing temperature was more conducive to the adsorption of Cu2+.

2019 ◽  
Vol 68 (7) ◽  
pp. 495-508
Author(s):  
Zhongmin Li ◽  
Wanwan Wu ◽  
Wenyan Jiang ◽  
Guangtao Wei ◽  
Yunshang Li ◽  
...  

Abstract The adsorption of Ni(II) by a thermo-sensitive adsorbent of methylcellulose/calcium alginate beads (CAMCBs) was studied using batch adsorption tests to determine the adsorption process and properties, the effects of adsorbent dosage, initial concentration, adsorption time and temperature. The adsorption process was further investigated using kinetics, isotherms and thermodynamic methods. The kinetics and isotherms studies showed the adsorption of Ni(II) on CAMCBs was fitted by the pseudo-second-order kinetic model and Langmuir isothermal adsorption model, respectively. The thermodynamic parameters indicated that the adsorption process was spontaneous and exothermic at lower temperature, and the entropy of the adsorption process was negative. In the study of regeneration, it was confirmed that under the temperature of 60 °C, the desorption agent of CaCl2 with concentration of 3 g·L−1 was more conducive to the desorption of Ni(II) from CAMCBs. Both adsorption capacity and mechanical strength of the used CAMCBs could be basically recovered to the level of fresh CAMCBs after desorption. The prepared CAMCBs had a good property of adsorption of Ni(II) and an excellent regeneration performance.


2010 ◽  
Vol 61 (9) ◽  
pp. 2293-2301 ◽  
Author(s):  
Danielle Bonenfant ◽  
Patrick Niquette ◽  
Murielle Mimeault ◽  
Robert Hausler

A study of adsorption/recovery of nonylphenol 9 mole ethoxylate (NP9EO) on a crosslinked β-cyclodextrin-carboxymethylcellulose (β-CD-CMC) polymer was carried out by ultraviolet-visible (UV-vis) and Fourier transform infrared (FTIR) spectroscopies. The adsorption was performed in mixtures containing 500 mg of the β-CD-CMC polymer and aqueous NP9EO solutions at concentrations 12–82 mg/L, whereas the recovery of NP9EO was effectuated by shaking the β-CD-CMC polymer loaded with methanol. The assays were made at 25°C and atmospheric pressure under agitation. The results have shown that the adsorption is a rapid process and the β-CD-CMC polymer exhibits a high NP9EO adsorption capacity of 83–92 w% (1.1–6.8 mg NP9EO/g β-CD-CMC polymer) dependent of the initial NP9EO concentration in liquid phase. This adsorption may involve the formation of an inclusion complex β-CD-NP9EO and a physical adsorption in the polymer network. The adsorption equilibrium measurements, which were analyzed using the Langmuir isotherm, have indicated a monolayer coverage and the homogeneous distribution of active sites at the surface of the β-CD-CMC polymer. Moreover, the negative value obtained for the free energy change (−13.2 kJ/mol) has indicated that the adsorption process is spontaneous. In parallel, the β-CD-CMC polymer exhibited a high NP9EO recovery efficiency of 97 w% that may occur through a decrease of binding strength between β-CD-CMC polymer and NP9EO. Together, these results suggest that the β-CD-CMC polymer could constitute a good adsorbent for removing nonylphenol ethoxylates from wastewater due to its high adsorption capacity and non-toxic character of β-CD and CMC to environment.


2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Xinrui Feng ◽  
Shaoshuai Sun ◽  
Ge Cheng ◽  
Lei Shi ◽  
Xiangshan Yang ◽  
...  

The magnetic adsorption material of polyaniline (PANI) with amino functional group combined with CuFe2O4 (CuFe2O4/PANI nanocomposite) has been described in this work. It has been characterized by TEM, XRD, XPS, BET, FTIR, and VSM, respectively. Significantly, it exhibits extremely high maximum adsorption capacity (322.6 mg/g) for removal of uranyl ions from wastewater at a pH of 4. The adsorption process is consistent with the quasisecond-order kinetic equation, and the isotherm and kinetic data are accurately described by the Langmuir isothermal adsorption model. Furthermore, the magnetic CuFe2O4/PANI displays stable adsorption performance for uranyl ions after five cycles of recovery in acid medium, which indicates it possesses good recovery due to its magnetism and excellent regeneration ability for reusability.


2015 ◽  
Vol 723 ◽  
pp. 697-700
Author(s):  
Xiao Dong Li

The adsorption performance of pummelo peel to Rhodamine B (RhB) was tested to study the adsorption regulation and optimal adsorption condition of pummelo peel to dye waste water. The results showed that the RhB removal rate of 0.4 g pummelo peel to 100 mL 140 mg·L-1 RhB reached above 83 % under the condition of 30 °C, pH 8 and 60 min. The theroretical saturation adsorpion amount of pummelo peel was 133 mg·g-1 at 30 °C. The main adsorption pattern of pummelo peel to RhB was physical adsorption adsorption including external liquid film diffusion, surface adsorption and particle internal diffusion. The isothermal adsorption equation and secondary adsorption rate equation of Langmuir could be used to describe the adsorption process of pummelo peel to RhB.


2019 ◽  
Vol 20 (1) ◽  
pp. 130 ◽  
Author(s):  
Ani Iryani ◽  
Hadi Nur ◽  
Mardi Santoso ◽  
Djoko Hartanto

Rhodamine B (RB) and Methylene Blue (MB) dyes adsorption using adsorbent ZSM-5 synthesized from Bangka kaolin were investigated in this study. The effects of the initial concentration, contact time and temperature on the adsorption process were also analyzed. The effect of the initial concentration and contact time played an important role in the adsorption process; however, the effect differs significantly in both dyes. The temperature plays little role in the dye adsorption process. The results showed the adsorption process occurred in ZSM-5 adhere to Langmuir isothermal adsorption model showing that the adsorption process occurred to be monolayer. Based on the kinetics studies, the pseudo-first-order kinetic model represents the adsorption kinetics that occurs for both dyes onto the synthesized ZSM-5. Thermodynamic parameters namely Gibbs free energy (ΔG°), standard entropy changes (ΔS°) and standard enthalpy (ΔH°) reveal that the adsorption process onto ZSM-5 for both dyes was spontaneous and exothermic.


2021 ◽  
Vol 10 (2) ◽  
pp. 94-98
Author(s):  
Hue Dang Thi Minh ◽  
Chau Tran Van ◽  
Giang Hoang Thi Linh ◽  
Luyen Tran Thi ◽  
Chinh Huynh Dang

Composite materials MIL-53(Fe)/Fe3O4 have been successfully synthesized on the basis of MIL-53 metal organic framework materials by hydrothermal method. Material characteristics were studied through XRD, SEM methods. The material has good adsorption capacity of the Congo Red pigment. The Congo Red adsorption activity of the composite material was investigated. The results showed that the adsorption efficiency of Congo Red of MIL-53(Fe)/Fe3O4 reached 98.89% after only 5 minutes, with the concentration of 2.227 mg/l in Congo red solution. The Congo Red adsorption process of MIL-53 (Fe)/Fe3O4 follows the Freundlich isothermal adsorption model.


2021 ◽  
Author(s):  
Loubna Jabir ◽  
Hayat elhammi ◽  
Mohammed Nor ◽  
Issam Jilal ◽  
Abderrahmane El Idrissi ◽  
...  

Abstract In this paper, a new green pH-sensitive cellulose based hydrogel (swelling rate ~ 1005 %) was successfully elaborated. However, the new EDTA crosslinked HEC was investigated as adsorbent materiel, which it showed high removal efficiency (~2000 mg.g-1) to aquatic micropollutants, especially methylene blue as cationic dyes model. The synthesis of HEC-EDTA at high advanced crosslinking degree (up to 92 %) that confirmed using structural analyzes (FTIR and 13C CP/MAS-NMR), was cried out using DAEDT and DMAP as acyl transfer agent, where the lamellar morphology (2D- microstructure) was highly suggested basing on the average functionality of the reaction system. The kinetic study showed that the adsorption process was better described by pseudo-second-order kinetic, where the thermodynamic parameters exhibited a negative effect of temperature indicating a physical adsorption process. In addition, the adsorption capacity was studied according to the experimental conditions (pH, contact time, concentration, etc.), and the Freundlich model revealed a strong correlation to the experimental results indicating an energetic heterogeneity of the surface active sites. In the other hand, molecular dynamics (MD) simulations were conducted and optimized using COMPASS II, where the results showed a good agreement with the experiment, and that basing on the intermolecular Non-covalent interaction, molecular structure and cluster configurations.


2018 ◽  
Vol 16 (1_suppl) ◽  
pp. 55-63
Author(s):  
Guangxin Wang ◽  
Yunchao Zhao ◽  
Bin Yang ◽  
Yongfa Song

Background: High purity cobalt has many important applications, such as magnetic recording media, magnetic recording heads, optoelectronic devices, magnetic sensors, and integrated circuits, etc. To produce 5N or higher purity cobalt in an electro-refining process, one of the challenges is to effectively reduce the Fe content of aqueous cobalt salt solution before electrolysis. This paper describes thermodynamic and kinetic investigations of the Fe adsorption process of a new sulfonated monophosphonic resin with the trade mark Monophos. Methods: Five cobalt sulfate solutions of different Co concentrations were prepared. Fe ions were removed from the solutions by ion exchange method using Monophos resin. Chemical analysis was carried out using a Perkin Elmer ICP-OES. Results: The initial Fe concentrations of about 0.9–2.0 mg/L can be reduced to about 0.3–0.8 mg/L, which is equivalent to an Fe removal rate of 60–67%. The Langmuir isothermal adsorption model applies well to the Fe removal process. A second-order type based on McKay equation fits better with experimental data than other kinetic models. The kinetic curve can be divided into two sections. For t < 30 min, particle diffusion may act as the controlling step, whereas chemical reaction may control the Fe adsorption process in the section t > 30 min. Conclusions: Monophos resin is effective for the removal of trace Fe from cobalt sulfate solution. This ion exchange process obeys the Langmuir isothermal adsorption model and the McKay equation of second-order kinetics.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Wenyan Du ◽  
Kangqi Shen ◽  
Yuruo Qi ◽  
Wei Gao ◽  
Mengli Tao ◽  
...  

AbstractRechargeable room temperature sodium–sulfur (RT Na–S) batteries are seriously limited by low sulfur utilization and sluggish electrochemical reaction activity of polysulfide intermediates. Herein, a 3D “branch-leaf” biomimetic design proposed for high performance Na–S batteries, where the leaves constructed from Co nanoparticles on carbon nanofibers (CNF) are fully to expose the active sites of Co. The CNF network acts as conductive “branches” to ensure adequate electron and electrolyte supply for the Co leaves. As an effective electrocatalytic battery system, the 3D “branch-leaf” conductive network with abundant active sites and voids can effectively trap polysulfides and provide plentiful electron/ions pathways for electrochemical reaction. DFT calculation reveals that the Co nanoparticles can induce the formation of a unique Co–S–Na molecular layer on the Co surface, which can enable a fast reduction reaction of the polysulfides. Therefore, the prepared “branch-leaf” CNF-L@Co/S electrode exhibits a high initial specific capacity of 1201 mAh g−1 at 0.1 C and superior rate performance.


Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4483
Author(s):  
Yuyingnan Liu ◽  
Xinrui Xu ◽  
Bin Qu ◽  
Xiaofeng Liu ◽  
Weiming Yi ◽  
...  

In this study, corn cob was used as raw material and modified methods employing KOH and KMnO4 were used to prepare activated carbon with high adsorption capacity for mercury ions. Experiments on the effects of different influencing factors on the adsorption of mercury ions were undertaken. The results showed that when modified with KOH, the optimal adsorption time was 120 min, the optimum pH was 4; when modified with KMnO4, the optimal adsorption time was 60 min, the optimal pH was 3, and the optimal amount of adsorbent and the initial concentration were both 0.40 g/L and 100 mg/L under both modified conditions. The adsorption process conforms to the pseudo-second-order kinetic model and Langmuir model. Scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Zeta potential characterization results showed that the adsorption process is mainly physical adsorption, surface complexation and ion exchange.


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